POS0561 PREVALENCE AND CHARACTERISTICS OF PATIENTS WITH “ARTHRALGIA AT-RISK” DEFINED ACCORDING TO THE RHEUMATOLOGIST AND THE NEW EULAR DEFINITION: A PILOT RETROSPECTIVE STUDY FOCUSSED ON REFERRAL TO A STRUCTURED EARLY ARTHRITIS CLINIC
Authors: S. Grignaschi, B. Xoxi, E. Bozzalla Cassione, T. Luvaro, M. I. Greco, I. Mazzucchelli, S. Bugatti, C. Montecucco, A. Manzo
Journal: Annals of the Rheumatic Diseases (2022)

Background The phase preceding the development of rheumatoid arthritis (RA) may contain a novel window of opportunity for disease prevention and control. Investigation of this phase at population level remain, however, very challenging in epidemiological terms due to the rarity of the events. Patients seeking medical attention with arthralgia at-risk, defined by an expert rheumatologist (clinically suspect arthralgia, CSA) or by the recent EULAR definition represent an attractive platform for the identification of both seropositive and seronegative disease subsets. Objectives The objective of this study was to explore the prevalence and characteristics of patients with different types of arthralgia, focusing on referral to the screening visit of an early arthritis clinic (EAC) as a putative enrichment strategy for pre-RA. Methods EAC first referrals from January 1 st 2019 to June 30 th 2021 were systematically reviewed through a retrospective evaluation of medical charts. Patient’s history, comorbidities, PROs and clinical examination were recorded by two expert rheumatologists blind to immunological, ultrasound and radiological data. Arthralgia cases, sub-classified according to risk-definitions, were recorded. Categories at-risk, according to the rheumatologist’s opinion and the EULAR definition, were characterized and compared to other arthralgia cases for clinical characteristics, imaging data and autoantibody status. Results Of the 363 patients referred to the EAC, 178 were characterized by peripheral arthralgia (swollen joint count=0) at screening visit (49%). Of these patients, 130 cases were characterized by recent-onset arthralgia (ROA) (&lt;12 months symptoms’ duration) (73% of the total). CSA, according to the rheumatologist’s opinion, was applicable to 71/178 total arthralgia patients (40%) and to 61/130 ROA patients (47%, recent-onset CSA, RO-CSA). Patients without CSA were characterized by undefined concomitant conditions or by “clinically suspect psoriatic or spondylarthritis arthralgia” (20/178, 11%). EULAR definition of arthralgia at-risk (&gt;2 items) was fulfilled by 53/71 CSA patients (74.6%) and by 52/107 (49%) patients not characterized by CSA (p=0.001 Chi-square test) (Figure 1). Figure 1. Early Arthritis Clinic first referrals from January 1 st 2019 to June 31 th 2021. Despite a similar clinical phenotype, comparative analysis between different arthralgia categories demonstrated a significant enrichment of RF and ACPA positivity (21% vs 4%, p=0,001, and 15% vs 3%, p=0.01) in both CSA and RO-CSA vs other groups. RO-CSA showed also an enrichment of hypogammaglobulynemia compared to other groups (13% vs 3%, p=0.03). After a stratification according to the fulfillment of the EULAR definition, both CSA and RO-CSA increased their differences compared to other groups regarding the elevation of C-reactive protein (CRP ≥0.5 mg/dl, p=0.006 and p=0.02 respectively). No epidemiological, clinical or imaging differences were observed through patient stratification according to the EULAR definition per se in the whole population. Conclusion Results of our pilot study provide evidence of the applicability of patient selection according to current arthralgia at-risk definition in the real-life setting of an EAC. Both CSA and RO-CSA appears as suitable niches for the enrichment of primary immunological and serological risk factors for RA (RF/ACPA, hypogammaglobulynemia and C-reactive protein). Current data confirm in an independent setting the importance of the rheumatologist’s perspective as a platform for appropriate application of the EULAR definition. Disclosure of Interests None declared.